Generally the in-pipe microrobots can be used for the mobile inspection of small diameter pipes. This paper describes the structure and design of an in-pipe microrobot. The suggested microrobot was built to use wheels for locomotion, and to be able to adapt its structure according to the inner diameter of the inspected pipe. Being powered using wires, the microrobot is not energetically autonomous. The microrobot is able to maintain its balanced state due to the pressure exerted by the wheels onto the inner surface of the pipe and it can adapt to pipe diameters ranged between 30 an 50 mm. The driving is achieved by using a DC motor with integrated gearbox. Motion transmission from the motor to the drive wheels is done by using three geared transmissions and the contact between the wheels and the pipe wall is continuously maintained trough a torsion springs mounted on the rotational joints of the wheel support elements. The testing of the microrobot was performed using a steel pipe with the diameter of 50 mm, placed both horizontally and vertically.

Bellows generally operate as pressure transducers, based on elastic deformation of their undulations, but presents a higher interest as actuators. After a short presentation of the actuators based on elastic / inflatable elements, some structural schemes of bellows - based actuating systems are given, FEM analysis is emphasized and initial prototypes are described.

The purpose of this paper is to validate the actuation of the positioning systems with a new type of pneumatic actuators based on corrugated tubular elements. The latter are also called bellows, usually operating as sealing elements or as pressure transducers.The CAD models of two positioning systems actuated with corrugated tube elements are given. The first one, with one degree of freedom, is driven by two bellows disposed in antagonist way, powered with different pressures, offering different displacements and adjustable stiffness. The second positioning system contains two overlapping platforms that can slide on two axis, (having two degrees of fredom), their operation being performed individualy with two pairs of bellows arranged in antagonist way, on two levels, disposed at 900 from each other. Pneumatic diagrams for the two positioning systems are given. Experimental prototypes are developed and the results of the first tests are presented.